Extech CG204 User Manual

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CG204-en-GB_v2.3 5/15

Calibration

CalibrationTypes

Performazerocalibrationandamulti‐pointcalibrationbeforeanycriticalmeasurementsaretaken.The

calibrationoptionsarelistedbelow.Readthedescriptionforeachandselectthebestmatc h foragiven

application.

1. ZeroPointCalibration:Performbeforeeachmeasurementsession.

2. OnePointCalibration:Useforhigh

accuracywithrepeatedtestsonaconstantcoatingthickness.

3. Multi‐PointCalibration:Useforhighaccuracywithinaknownrangeofcoatingthickness.

4. Calibrationforshot‐blastedsurfaces.

CalibrationConsiderations

Thecalibrationsamplemustcorrespondtotheproductsampleinthefollowingways:

 Curvatureradius

 Substratematerialproperties

 Substratethickness

 Sizeofmeasurementarea

 Thepointatwhichthecalibrationismadeonthecalibrationsamplemustalwaysbeidenticalwith

thepointofmeasurementon

theproductitself,especiallyinthecaseofcornersandedgesof

smallparts.

Toachievethehighestmeasurementaccuracy,performseveralcalibrationsinsuccession(forzerovalues

andcalibrationfilmvalues).

Preparingforcalibration

1. Cleantheprobetip(grease,oil,metalscrap,andtheslightestimpuritywillaffectmeasurementand

distortreadings).

2. SwitchthemeterON(ata10cm[4”]minimumdistancefromanymetal).

3. Readythesuppliedmetalsubstratesamplesandnecessaryfilms(suppliedcalibrationreference

films).

4. Setthemeter

to:

a. DIR:(MENU‐OPTIONS‐WorkingMode‐Direct)

b. CONTINUOUS:(MENU‐OPTIONS‐MeasureMode‐Continuousmode[flashingunitsindicator])

c. MAX:(MENU‐OPTIONS‐LCDStatistic‐Maximum).

5. Themeterisnowreadyforcalibration.

6. YoushouldperformaZerocalibrationpriortoathicknesscalibration.



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Extech ‎CG204 CG204 Coating Thickness Tester